This invention relates to “safety” covers for swimming pools for keeping debris from entering the pool water and preventing water puddles on the upper surface of the pool cover.
Pool covers are known and examples are disclosed, for example, in U.S. Pat. No. 3,184,764 (West) U.S. Pat. No. 4,233,695 (Rowney) and U.S. Pat. No. 5,259,078 (Crandall), the subject matter of which are incorporated herein by reference. A principal purpose of such pool covers is to prevent entry of debris into the pool during periods of non-use, e.g. during extended periods of time from the end of one swimming season to the beginning of the next.
A principal purpose of a “safety” pool cover is to prevent harm to persons, particularly small children and animals venturing onto the pool cover. One particular hazard is the formation of puddles on the upper surface of the pool cover, such puddles creating drowning hazards. This problem is particularly avoided by the present invention
Some pool covers are made to be water impervious, for preventing dirty water and debris from entering the underlying pool, and are tautly suspended over the surface of the pool. Inevitably, the cover sags between its points of suspension thereby forming one or more dependent pockets which tend to deepen as rain water and debris collect on the cover. A known solution for preventing the accumulation of water in the pool cover pockets is to provide drain openings through the pool cover at the bottoms of the pockets for draining the otherwise accumulating water directly into the underlying pool. The drain openings are covered by debris collecting filters whereby only relatively clean, filtered water enters the pool.
The filtered drain openings may be included in the pool covers during manufacture and are located on the covers at the anticipated lowermost cover portions when the covers are mounted on the pools. A somewhat unexpected problem is that identical pool covers mounted on identical pools will often assume different drape configurations including differently located pockets of maximum sag. One cause for this, for example, is the use of different tensions in the means, straps, springs and the like, used for mounting the pool covers on the different pools. To the extent that the existing drain openings are spaced from the actual points of maximum sag of the pool covers, pools of water collect on the covers. This is avoided in accordance with this invention.
Another principal purpose of a “safety” pool cover is that it be adequately strong to fully support the weight of a human adult walking across the surface of the pool mounted cover. A problem with known pool covers of the type containing drain openings is that the presence of the openings through an otherwise continuous pool cover provides regions of reduced strength where tearing and rupture of the pool cover can occur. This problem is avoided by pool covers embodying the invention.
Another problem with known pool covers is that the drain openings allow sunlight to pass through the covers. The sunlight provides sufficient energy to allow the growth of algae and like plants or fungi within the water in the pool.